Servo-motor for aeroplanes



Oct. 30, 1923. 1,472,257

M. M. TITTERINGTON SERVO MOTOR FOR AEROPLANES Filed Nov, 9, 1917 2Sheets-Sheet 1 IN VE IV TOR Morr/sMTner/ggton Oct. 30, 1923. 1,472,257

M. M. TITTERINGTON SERVO MOTOR FOR AEROPLANES Filed Nov. 9, 1917 2Sheets-Sheet 2 INVENTOH Morris-MT/Cte r/ngton Patented Oct. 30. 1923.

UNITED STATES PATENT OFFICE.

MORRIS M. TITTERINGTON, OF

BROOKLYN, NEW YORK, ASSIGNOR TO THE SPERRY GYROSCOPE COMPANY, OFBROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

SERVO-MOTOR FOR AEROPLANES.

Application filed November 9, 1917. Serial No. 201,057.

To all whom it may concern:

Be it known that I, Monms M. Trrrna- ING'I'ON, a citizen of the UnitedStates of \merica, residing at 64 Remsen Street, Brooklyn, in the countyof Kings and State of New York, have invented certain new and usefulImprovements in Servo-Motors for Aeroplanes,

a specification. This invention relates to means for controlling theposition of a device by means of a manually operable membereitherdirectly orthrough a motor. More particularly the inventionrelates to mechanism for controlling the position of the controllingplanes of aircraft, although it may be employed in other connections.

Some modern aeroplanes, especially bombing planes, are of such designthat the actuation of the controlling planes by the pilot or pilotsrequires the expenditure of considerable physical effort. In order toavoid this a servo-motor is provided for actuating the planes whichservo-motor is controlled by a steering wheel or other manually operablemember.

()ne of the principal objects of the present invention is to provide adevice in! which the servo-motor, its manually operable controllingmember and a driven shaft operated by said motor and adapted to be dire:tly connected to a controlling plane,

. are all embodied in a single compact unitary structure adapted to beapplied to any aeroplane or other aircraft. ,v

Another object is to provide a device in which the driven shaft may beactuated directly by means of the manually operable member, preferablyWithout car ing the motor and its gearing as a load. ther objects andadvantages will appear as the invention is hereinafter developed.

Referring to the drawings which illus- 0 trate what I now consider thepreferred form of my invention:

Fig. 1 is a central longitudinal section of one form of my device showndetached and disconnected from the aeroplane.

Fig. 2 isan end elevation of the gear casing looking in the direction ofthe arrow 2 in Fig. l and certain parts.

Fig. 3 is a detail of one form of circuit ,a preferred form of of whichthe following is inafter term a, servo-motor,

cap 19 maybe screwed on the controller for the motor, with the coverplate removed.

Fig. 4 is a wiring diagram illustrating connections.

Fig. 5' illustrates, in a somewhat diagrammatic manner, my inventionconnected to a controlling lane and provided with an auxiliary controling wheel.

Fig. 6 is a sectional detail taken on the line 6-6 of Fig. 1.

Fig. 7 is a diagram of ,a modifiedform of the invention. v

Calling attention to Figs. 1 and 5 it will be seen that I have provideda frame or casing 1 adapted to be secured to an aircraft or other deviceby means of legs 2 and provided with a detachable lid or closure 3. Amotor shaft 4 and what I term a driven shaft 7 are journaled in theframe or casing 1 preferably by means of ball bearings 6 and 8,respective] or other anti-friction. bearings. An additional bearing 10may be provided, in the partition 9 within casing 1 for shaft 7. 1

While the motor 11, which I will heremay be mount ed within casing 1 Iprefer to mount it exteriorly thereof, but detachably secured The motoris preferably of steel, cylindrical in form and provided with coolingribs 12. The cylinder 13 is shown as having detachably secured theretoat its and opposite casing 1, a journal bracket 15, screws 16 formingthe connection. The bracket 15 besides carrying a ball bearing 17 forthe motor shaft 4 is provided with an exteriorly screw threadedoutwardly projecting sleeve or hub 18. A cup-shaped last mentionedmember thereby rendering the gear casing 1 and motor casing both dustand Weatherproof.

Suitable gearing is provided between the motor shaft 4 and the drivenshaft 7. I prefer to mount this gearing within the casing 1 and to makeone of the gears disengageable from its corresponding gear by means of amanually operable member exterior to the casing l, for a purpose whichwill appear hereinafter. The shaft 41 carries a pinion 21 which mesheswith a gear 23 keyed thereto as by means of screws. frame or casing 13or otherwise secured to a shaft 27 rotatable in journals 26 in a fixedsleeve 25. The latter is carried by one side of easing 1 and by thepartition 9. Preferably the end 22 of shaft 4 is threaded so that alarger pinion slipped ovcr pinion 21 may be secured in place by screwinga nut, similar to the nut 24 of shaft 27, upon said threaded end. Thegear 23 may be replaced by a different gear simply by removing nut 24,so that the gear ratio between shafts 4 and 27 may be readily changed.The shaft 27 carries a pinion 28 which meshes with the gear 29, a slot40 being provided in sleeve 25 for this purpose. The gear 29 isrotatably mounted in a frame 30 pivoted at one end on sleeve 25 andnormally in the position shown in Fig. 2. A pinion 31 rigidly mounted onthe same shaft as gear 29 is shown engaging a gear 32 keyed to shaft 7.

The gear train above described forms a driving connection between themotor shaft 4 and driven shaft 7. Under certain conditions it isdesirable to break this connection. I have accordingly provided a cam33, mounted on a shaft 41, within the gear casing 1, and betwen thebifurcated end of the pivoted frame 30. This cam may be operated by ahand lever 36 on shaft 41 on the exterior of easing 1. In the positionshown (see Fig. 2) the cam 33 holds the frame 30 down so that pinion 31is held in mesh with gear 32. By throwing the lever 36 in a.counterclockwise direction the cam will raise the frame 30 and pull thepinion 31 out of mesh with its gear wheel 32. A sector 34 may be fixedon the cam shaft 35 and may be provided with a locking pawl 37 mountedon casing 1 for automatically locking the cam in either of its twopositions.

Instead of using a. wind-driven servomotor I prefer to employ anelectric motor as the device can thereby be made much more compact.While this motor could assume a variety of types I have illustrated butone, i. e., a compound wound D. C. motor 11. The latter comprises theusual armature 5, a series field 42 and a shunt field 43.

I also provide an electrically controlled brake for the armature shaft 4which will automatically bring the said shaft rapidly to rest when themotor is deenergized and which normally locks the parts againstmovement. This brake is preferably mount.- ed within the. cylinder 13and comprises an annulus 45 of magnetic material and a disk 48. One ofthese elements, for example, the annulus 45. is secured to the cylinder13 while the other is slidably but non-rotatably secured to shaft 4 by akey or other suitable means. A spring 49 may be provided for urging thedisk 48 to disengaged position and a coil 46 may be provided in theannulus 45 for the purpose of pulling said disk to active or brakingposition. The adjacent portions of the annulus and disk are preferablyfaced with friction material and 47 respectively. Obviously when coil 46is energized the disk 48 will engage the annulus and brake the motorshaft 4.

Preferably the brake should be adjustable and for this purpose theannulus 45 is screwthreaded on its exterior and the cylinder 13 isprovided with corresponding internal serew-tln'eads. Obviously byturning the annulus the latter is moved in a direction toward or awayfrom the disk 48 so that the braking torque for a given value ofampere-turns in coil 46 is varied. The adjustment may be effected fromthe exterior of the motor casing by removing the door 51 and moving apin 52 inserted in any one of a circumferential series of radiallyextending holes in the annulus, a circumterentia-lly extending slot 53being provided in the cylinder 13 for permitting the above operation.When adjusted, the annulus may be locked against turning by inserting apin in each of the holes nearest the ends of slot The driven shaft 7 isalso adapted to be driven by a wheel, or other manually operable member64 mounted thereon, preferably through a lost motion connection. The hub56 of the member 64 is shown loosely mounted on a sleeve keyed orotherwise secured to shaft 7 and a nut 57 is provided on shaft 7 forholding the said hub and sleeve in position. The sleeve 55, as shown inFigs. 1 and 6,,is provided with a downwardly extending arm 58 carrying apost 59 adapted to be engaged by one or the other of opposite sides of asleeve 61 secured in a bore in the hub 56. The wheel 64 may becentralized with respect to post 59 by means of a pair of springs 65(see Fig. 6) secured at one end to hub 56 by means of a through-bolt 63and engaging the arm 58 at their free ends.

The wheel 64 besides being so connected as to operate shaft 7 directlymay also be provided with a circuit controller for operating the saidshaft through the motor 11. One form of controller is shown in Fig. 1 atand in detail in Fig. 3. The post 59 is provided with a reduced portion62 which engages in a slot 74 (see Fig. 3) in a crank arm 71 secured toa shaft 72 rotatably mounted in the base 75 of the circuit controller.The base 75 may be secured to the steering wheel in any suitable manner.The other end of shaft 72 has secured thereto an arm 73 provided with aplurality of inwardly extending pins 76, 77 and 78 adapted to operatethe various contacts on movement of arm 73. Thus pin 76 is adapted tomove one or the other of contact levers 79 away from the bridging piece80 and into contact with a corresponding contact lever 81. A spring 82may be provided between levers 79 for the purpose of lit biasing thelatter to bridge-piece-engaging position, and a spring 83 may beprovided between the levers 81 for the purpose of normally holding thelast mentioned levers against stop pins 84 but permitting movement awayfrom the stop pins. The pins 77 and 78 are each adapted to engage acorresponding pivoted contact lever 86 and cause the latter to breakcontact with a corresponding fixed contact 85. The levers 86 may bebiased to contact position by means of a spring 87 engaging at each ofits ends one of said levers and at its middle the bottom portion 88 of aU-shaped member 89 secured to the pivots of levers 86. The

parts are preferably so designed as to operate in the followingsequence. When wheel 64 -1S turned in either direction, arm 73 1s movedin a correspondlng direction causing a corresponding one of pins 77, 78

to engage its contact lever 86 to move the latter away from its contact85. The pin 76 then engages a corresponding one of levers 79 to causethe latter to disengage bridge-piece and to engage its contact lever 81.All of the above described operation takes place before the post 59 isengaged by sleeve 61. When the wheel is allowed to assume centralposition with re: spect to post 59 the contact levers are re stored bytheir springs to the normal position shown in Fig. 3. 'A cover plate 90adapted to screw on base 75 may be provided to protect the circuitcontroller 70.

As the wheel 64 turns with respect to the motor 11 and the brake, Iprovide the shaft 7 with a longitudinal bore indicated by dot-ted linesat 92 in Fig. 1. The electrical conductors between the circuitcontroller 70 and the controlled devices may be led through this boreand each connected to a corresponding slip ring 93 secured on the innerend of said shaft 7. Brushes 94 mounted on a holder 95 on partition 9and engaging the slip rings, may be utilized to connect, electrically,the bore contained wires to the motor and brake as indicated in Fig. 4.

The last mentioned figure is illustrative of a preferred form ofelectrical connections. Energy may be supplied from any suitable sourceof E. M. F. through a switch 102 to line wires and 101. By connectingthe shunt field across line 100, 101, at all times, as indicated, themotor will be more sensitive in responding, i. e., in starting andstopping, than otherwise. The series field 42 is shown connected to linewire 101. and to a conductor 106 connected to both of contact levers 81,contact levers 79 each being connected to a corresponding one of thebrushes of armature 5 by means of conductors 107 and 108. Bridge piece80 is shown connected to the line wire 100 by means of a common return103. The

brake magnet 46 is shown connected at one end to'line wire 101 and atthe other end to a contact 85 by means of the wire 104, the other ofcontacts 85 is connected ti common return 103 and levers connected.

The operation of my invention as thus far described is substantially asfollows. Assuming that switch 102 is closed and the handle 36 in theposition shown in Fig. 2 and it is desired to turn the driven shaft. 7in one direction or the other, the hand wheel 64 is simply turned in thedesired direction to asufficient extent to operate the circuitcontroller 70. This causes the brake magnet to release the brake, thearmature short circuit to be broken and the armature to be energized insuch a direction as to drive the shaft 7 in the same direction as thewheel 64 is turned. The motor 11 will continue to drive shaft 7 untilthe wheel 64 is allowed to resume its normal position with respect topost 59 when the armature energizing circuit will be broken, thearmature short-circuited, thereby producing a braking effect due to thegenerz-itor action of the armature and the brake magnet 46 will bere-energized to apply the friction brake, rapidly bringing the motor andshaft 7 to rest; If for any reason such. as of the motor, it is desired.to operate the shaft 7 directly by the wheel 64 the switch 102 may beopened, or the hand e 36 may be thrown in the direction of the arrow inFig. 2, or both of these operations may be performed. On pulling switch102 or on failure of the source of supply the motor brake will bereleased so that the shaft 7 may then be rotated by the wheel 64. Bythrowing lever 36 the shaft 7 is disconnected from the motor and trainof gears and therefore much easier to rotate .by the hand wheel.

While my invention is applicable to various devices I have illustratedit in connection with a controlling plane of an aeroplane. Thus asprocket wheel 110 secured to shaft 7 by being connected to sleeve 55may actuate a chain 111 and wires 112 to actuate a controlling plane 113(see Fig. 5). An auxiliary manually operable wheel or other member 64may be chain connected to a sprocket 115 provided on hand wheel 64 forconvenience in operation when there are two pilots.

The circuit controller 70 may assume the form illustrated in Fig. 7 anddesignated as 70'. In this form the arm 73' corresponds to the arm 73shown in 'Fig. 3 and is actuated in the same way. The arm 73 is normallyin engagement with a contact 303 but is adapted to disengage thiscontact and engage either of the contacts 304 or 305, epending on thedirection in which steering wheel 64 is turned. With this form of con-86 are electrically jamming l troller, relay mechanism shown as relays301 and 302 are interposed between the controller and the controlledelements.

In Fig. 7 the elements designated by". reference numerals with rimesadded, correspond to the elements s iown in Fig. 4; and the remainingfigures. The relay coils 301 and 302 are shown each connected on oneside to a line wire 100 while the other side of each of the relay coilsis connected to a corresponding contact 305 and 304; the arm 73 beingconnected to the opposite line wire 101'. The armatures of the tworelays are shown connected across the terminals of the motor armature 5.The front contacts of the relays are connected together and to one sideof the line, while the back contacts, which are also connected together,are connected to the opposite side of the line.

It will be noted that as in the other form of connections the leads fromthe circuit controller 70 are connected through brushes 94' and sliprings 93 to the controlled elements. The remaining connection in Fig. 7,as well as the operation of this form of the invention will be readilyapparent, without further description, to any person skilled in the art,in View of the explanation set forth in connection with Fig. 4.

In accordance with the provisions of the patent statutes, I have hereindescribed theprinciple of operation of my invention, together with theapparatus, which I now consider to represent the best embodimentthereof, but I desire to have it understood that the apparatus shown isonly illustrative and that the invention can be carried out by othermeans. Also, while it is designed to use the various features andelements in the combination and relations described, some of these maybe altered and others omitted and some of the features of eachmodification may be embodied in the others without interfering with themore general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patcut is:

1. In an aircraft steering apparatus, abase, a servo-motor'mounted onsaid base, a shaft, a gearing connection between said motor and shaft,manually operated means for breaking said gearing connection, a steeringwheel on said shaft and a motorcontrolling switch operated by said wheelto render the motor effective to drive said shaft, saidmanually-operated means enabling said steering-wheel to drive said shaftindependently of said gearing.

2. In a controller device, a motor having a shaft, a second shaft,reduction gearing connectin said motor shaft and said second sha t, amanually-operable member whereby said gearing may be renderedineffective so that said second shaft is disconnected from said motorshaft, and a sec ond manually operable member connected to said secondshaft whereby the latter may be operated independently of the gearing ormotor.

A controller handle including a casing, a. motor having a shaftjournalled in said casing, a second shaft journalled in said casing,reduction gearing connecting said motor shaft and said second shaft, amanually operable member carried by said second shaft and means fordisconnecting said two shafts at a point adjacent said second shaftwhereby said member may drive the same without driving the gearing ormotor.

4. In an aircraft steering apparatus, a base, a servo-motor mounted onsaid base, a shaft rotatably supported on said base, a gearingconnection between said motor and shaft, means for breaking said gearingconnection at a point adjacent said shaft and remote from saidservo-motor, a steering wheel on said shaft and a motor controllingswitch operable by said steering wheel, said means for breaking saidgearing connection enabling said steering-wheel to drive said secondshaft independently of said gearing.

5. A controller handle for airplanes including a casing, a motor havingits shaft journaled in said casing, a second shaft journaled in saidcasing, means mounted in said casing forming a driving connectionbetewen said shafts. means including a handle mounted on said casing forbreaking said driving connection and a manually operable member carriedby said second shaft.

6. A controller handle for airplanes in cluding an enclosed servo-motor,an electrically controlled brake within the motor frame having a partsecured to the shaft of said motor and a part threaded in said casingand means for adjusting said last named part from without the motorframe.

7. In combination, a servo-motor, a shaft, double reduction gearsconnecting said motor and shaft, a manually-operable member mounted onsaid shaft, means responsive to operation of said member for causingoperation of said motor, and means for rendering one set of reductiongears ineffective so that said manually-operable member may operate saidshaft independently of said motor and gears.

In testimony whereof I have afiixed my signature.

1 MORRIS M. TITTERINGTON.

